All you need to do is carefully dismantle the 9-pin dock connector on your VGA cable and solder on a few wires from an old USB cable. Your new super cable will be able to charge and output video to the TV, all from one dock connector. Sure, you could always buy a cable like this in the store, but we all know Apple cables aren't cheap — so if you have the know-how and a USB cable lying around, there's no reason not to throw it together yourself. Hit the link for the full how-to.
Adding USB (Charging) to iPad VGA adapter [Instructables]